Create models and modify the handler to take a struct

cmd/web/handlers.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"myapp/internal/models"
 	"net/http"
 )
 
@@ -46,7 +47,20 @@ func (app *application) PaymentSucceeded(w http.ResponseWriter, r *http.Request)
 
 // ChargeOnce displays the page to buy one widget
 func (app *application) ChargeOnce(w http.ResponseWriter, r *http.Request) {
-	if err := app.renderTemplate(w, r, "buy-once", nil, "stripe-js"); err != nil {
+	widget := models.Widget{
+		ID:             1,
+		Name:           "Custom Widget",
+		Description:    "Paris 2024",
+		InventoryLevel: 10,
+		Price:          1000,
+	}
+
+	data := make(map[string]interface{})
+	data["widget"] = widget
+
+	if err := app.renderTemplate(w, r, "buy-once", &templateData{
+		Data: data,
+	}, "stripe-js"); err != nil {
 		app.errorLog.Println(err)
 	}
 }

internal/models/models.go

@@ -0,0 +1,34 @@
+package models
+
+import (
+	"database/sql"
+	"time"
+)
+
+// DBModel is the type for database connection values
+type DBModel struct {
+	DB *sql.DB
+}
+
+// Models is the wrapper for all models
+type Models struct {
+	DB DBModel
+}
+
+// NewModels returns a model type with database connection pool
+func NewModels(db *sql.DB) Models {
+	return Models{
+		DB: DBModel{DB: db},
+	}
+}
+
+// Widget is the type for all widgets
+type Widget struct {
+	ID             int       `json:"id"`
+	Name           string    `json:"name"`
+	Description    string    `json:"description"`
+	InventoryLevel int       `json:"inventory_level"`
+	Price          int       `json:"price"`
+	CreatedAt      time.Time `json:"-"`
+	UpdatedAt      time.Time `json:"-"`
+}